Zoom lens, camera apparatus and portable information terminal apparatus

ABSTRACT

A zoom lens having five lens groups arranged in succession. The zoom lens is configured such that when zooming from a short focal length end toward a long focal length end, the second lens group lens moves toward the third lens group and the fourth lens group moves toward a side of the third lens group, and the fifth lens group corrects the zooming and a shift in a position of an imaging plane of the zoom lens caused by movement of the third lens group and the fourth lens group.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a compact zoom lens suitable foruse in video cameras and still video cameras, a camera apparatus usingthe zoom lens, and a portable information terminal apparatus.

[0003] 2. Discussion of the Background

[0004] In a zoom lens for use in video cameras and still video cameras,recently, as demands for a higher zooming ratio, a wider field angle anda higher resolution increase, and at the same time for meeting demandsfor a smaller size, a lighter weight and a reduced cost, reducing theoverall length and the outer diameter of the zoom lens and decreasingthe number of pieces of lens composing the zoom lens are becomingimperative.

[0005] As a zoom lens for meeting the above-described demands, a type ofzoom lens has been proposed, in which, in order from the object side, afirst lens group having a positive refracting power, a second lens grouphaving a negative refracting power, a third lens group having a positiverefracting power, a fourth lens group having a positive refractingpower, and a fifth lens group having a positive refracting power arearranged. By moving the second lens group toward the imaging plane side,zooming of the zoom lens from the short focal length end to the longfocal length end is performed, and a shift in the position of an imagingplane of the zoom lens due to the movement of the second lens group forthe zooming is corrected by the fourth lens group.

[0006] Japanese Patent Laid-open Publication No. 6-180424, JapanesePatent Publication No. 3109342, and Japanese Patent Laid-openPublication No. 9-90221 describe examples of zoom lenses of such type.In each of the zoom lenses of these examples, a shift in the position ofan imaging plane occurring in connection with zooming is corrected bymovement of the fourth lens group.

[0007] Each of the zoom lenses having five lens groups described in theabove publications, respectively, is configured such that the fourthlens group is moved solely for correcting a shift in the position of animaging plane occurring in connection with zooming, and the movement ofthe fourth lens group does not contribute to the zooming at all. Thefunction of zooming is mostly performed by the second lens group. Forthis reason, the moving amount of the second lens group for zooming islarge, and as a result, the first lens group must be arranged at adistant position from an aperture diaphragm arranged in the third lensgroup. This leads to increasing the size of the first lens group andfurthermore to increasing the overall size of the zoom lens.

SUMMARY OF THE INVENTION

[0008] The present invention has been made in view of theabove-discussed and other problems and addresses the above-discussed andother problems.

[0009] Preferred embodiments of the present invention provide a novelzoom lens that has a high zooming ratio exceeding 4.5 times while beingextremely small in the outer diameter and the overall length thereof anda wide field angle with a half field angle at the short focal length endof 30° or more, and that can attain a high resolution. The preferredembodiments also provide a camera apparatus using the zoom lens, and aportable information terminal apparatus using the camera apparatus.

[0010] According to a preferred embodiment of the present invention, azoom lens includes a first lens group having a positive refractingpower, a second lens group having a negative refracting power, a thirdlens group having a positive refracting power, a fourth lens grouphaving a positive refracting power, and a fifth lens group having apositive refracting power. The first lens group, the second group lens,the third lens group, the fourth lens group, and the fifth lens groupare arranged in succession. The zoom lens is configured such that, whenzooming from a short focal length end toward a long focal length end,the second lens group lens moves toward the third lens group and thefourth lens group moves toward a side of the third lens group, and thefifth lens group corrects the zooming and a shift in a position of animaging plane of the zoom lens caused by movement of the second lensgroup and the fourth lens group. When a distance from a first lenssurface of the zoom lens at the long focal length end to the imagingplane is Σd, a synthesized focal length of the first lens group throughthe fifth lens group is fw, and a synthesized focal length of the firstlens group through the fifth lens group is ft, a following conditionalformula is satisfied: 1.45<Σd/(ft−fw)<2.2.

[0011] Thus, the above-described zoom lens is configured such that whenzooming, the fourth lens group is also moved to perform a portion of thezooming and a shift in the position of the imaging plane of the zoomlane involved in the zooming is corrected by moving the fifth lensgroup. Thereby, the moving amount of the second lens group can besuppressed small, so that the distance of the first lens group from anaperture diaphragm can be reduced and the outer diameter of the firstlens group can be made relatively small, and at the same time, theoverall size of the zoom lens can be made relatively small. Further,freedom in enhancing the performance of the zoom lens is increased bymoving the fifth lens group, so that enhancement of the performance ofthe zoom lens can be achieved.

[0012] The above conditional formula specifies an overall size of thezoom lens, and if the upper limit is exceeded, the overall length of thezoom lens will increase, the outer diameter of the first lens group willincrease, the cost of the zoom lens will increase, and the size of acamera using the zoom lens will increase. If the lower limit isexceeded, the power of each lens group will be too strong, so thatsatisfactory imaging performance will not be obtained.

[0013] For achieving a higher performance of the zoom lens, it ispreferable that the zoom lens is configured such that the followingconditional formula is satisfied: 1.6<Σd(ft−fw)<2.2.

[0014] In the above-described zoom lens, the first lens group may bemounted at a fixed position. That is, the first lens group may be afixed lens group that does not move when the zoom lens is zoomed andwhen a portion of lens groups moves for focusing. For realizing movingof moving lens groups of a zoom lens with a simple mechanism, it ispreferable that the zoom lens is configured such that the first lensgroup is fixed. The first lens group has a largest outer diameter amongthe lens groups constituting the zoom lens, and consequently, the firstlens group is relatively heavy. Accordingly, it is hard to realizemoving of the first lens group with a simple mechanism and reduced powerconsumption. Further, if the zoom lens is configured such that focusingis performed by the first lens group, the peripheral light quantity at ashort photographing distance is greatly reduced as a result of movementof the first lens group, which is undesirable. For avoiding thisdisadvantage, the first lens group must be made extremely large. Byconfiguring the zoom lens such that the first lens group is fixed asabove, as might be expected, the distance from the first lens surface ofthe zoom lens to the imaging plane is constant through the entirezooming range.

[0015] In the above-described zoom lens, an aperture diaphragm may bearranged in the vicinity of the third lens group, and in particular, itis preferable that the aperture diaphragm is arranged at a most outsideposition of the third lens group at the side of the second lens group.Further, the third lens group including the aperture diaphragm may bemounted at a fixed position.

[0016] Generally, a shutter is provided at the position of the aperturediaphragm. A mechanism for moving the shutter is relatively complicated.Further, if the shutter is configured to be moved, vibration at the timeof driving the shutter tends to be transmitted to other parts of thezoom lens. This causes deterioration of the performance of the zoomlens, e.g. image burring. Thus, it is preferable that the third lensgroup including a shutter is not moved.

[0017] In the above-described zoom lens, focusing may be performed by amethod of letting out the entire portion of the zoom lens, a method ofmoving a light receiving element such as a CCD, or a so-called internalfocusing method in which lens groups other than the first lens group ismoved. Specifically, in the above-described zoom lens, focusing of thezoom lens may be achieved by movement of the fifth lens group.Generally, the moving amount of a focusing lens group of a zoom lenswhen focusing on an object at a same photographing distance is small atthe short focal length end and is greater as the focusing lens group iscloser to the long focal length end. In the above-described zoom lens ofthe present invention, the distance between the fourth lens group andthe fifth lens group is small at the short focal length end and isgreater at the long focal length end. Accordingly, a space in which thefifth lens group is moved for focusing can be obtained withoutinterfering with the fourth lens group at any zooming position. Further,the zoom lens of the present invention is configured such that a shiftin the position of an imaging plane involved in zooming the zoom lens iscorrected by the fifth lens group. Therefore, the zoom lens of thepresent invention has an advantage that a moving mechanism and a controlmechanism for correcting a shift in the position of an imaging plane andthose mechanisms for focusing can be combined.

[0018] The above-described zoom lens may be configured such that when asynthesized focal length of the first lens group is f1 and a synthesizedfocal length of the first lens group and the second lens group at thelong focal length end is f12t, the following conditional formula issatisfied: −1.8<f12t/f1<−1.1.

[0019] In the above conditional formula, f12t/f1 represents a zoomingratio of the second lens group at the long focal length end, and formaking the overall size of the zoom lens small, it is preferable thatthe above conditional formula is satisfied. If the upper limit isexceeded, contribution of the second lens group to a zooming functionwill be excessively small, so that a change in an entrance pupil whenthe zoom lens is zoomed will be reduced, and when the diameter of anaperture diaphragm is fixed, a change in the F number at the long focallength end will be increased relative to that at the short focal lengthend. If the lower limit is exceeded, contribution of the fourth lensgroup to a zooming function will be excessively small, so that the powerof the first lens group will be too strong and aberration in the firstlens group will be excessively large, and thereby satisfactory imagingperformance will not be obtained.

[0020] For further reducing the overall size of the zoom lens, it ispreferable that the zoom lens is configured such that the followingconditional formula is satisfied: −1.7<f12t/f1<−1.2.

[0021] Further, the above-described zoom lens can be configured suchthat when a distance between the first lens group and the second lensgroup at the short focal length end is d1w, a distance between the firstlens group and the second lens group at the long focal length end isd1t, a distance between the third lens group and the fourth lens groupat the short focal length end is d3w, and a distance between the thirdlens group and the fourth lens group at the long focal length end isd3t, the following conditional formula is satisfied:0.3<(d3w−d3t)/(d1t−d1w)<0.8.

[0022] The above conditional formula specifies a ratio between a movingamount of the fourth lens group and that of the second lens group whenthe zoom lens is zoomed. For reducing the size of the zoom lens of thepresent invention, one may increase the moving amount of the fourth lensgroup to a certain extent. If the ratio exceeds the lower limit, themoving amount of the second lens group (the denominator of the aboveconditional formula) will be increased or the moving amount of thefourth lens group (the numerator of the above conditional formula) willbe decreased, so that a portion of a zooming function performed by thefourth lens group will be reduced, and thereby the size of the zoom lenswill not be reduced. Conversely, if the ratio exceeds the upper limit,the moving amount of the fourth lens group will be increased, a portionof a zooming function performed by the fourth lens group will beincreased, and a portion of the zooming function performed by the secondlens group will be decreased, so that satisfactory zooming will not beperformed, thereby causing deterioration in the imaging performance.

[0023] For further reducing the overall size of the zoom lens andenhancing the zooming performance, it is preferable that the followingconditional formula is satisfied: 0.4<(d3w−d3t)/(d1t−d1w)<0.7.

[0024] Further, the above-described zoom lens may be configured suchthat each of the first lens group and the second lens group includesthree pieces of lens, the fourth lens group includes four pieces oflens, and the fifth lens group includes one piece of lens, and such thateach of the second lens group through the fifth lens group includes oneor more non-spherical surfaces. For obtaining a high performance zoomlens, each aberration must be suppressed small. For correcting eachaberration satisfactorily, one may increase the number of lensesconstituting the zoom lens to a certain extent, and aberration in eachlens must be suppressed small. However, if the number of lensesincreases, the thickness of each lens group increases, so that theoverall size of the zoom lens cannot be reduced, and at the same timethe construction of the zoom lens is complicated, causing the cost ofthe zoom lens to be increased.

[0025] Therefore, in the above-described zoom lens of the presentinvention, each of the first lens group and the second lens group isconstituted of a relatively small number of lenses, i.e., three piecesof lens, and the fourth lens group is constituted of four pieces of lensso that an effect of deterioration in the imaging performance due todecentering of each lens of the fourth lens group is decreased. Further,the fifth lens group is constituted of one piece of lens. When the fifthlens group is moved for correcting a shift in the position of an imagingplane and for focusing, because the number of lenses constituting thefifth lens group is small and thereby the fifth lens group is light, thefifth lens group can be moved by less energy. For maintaining asatisfactory imaging performance in a zoom lens constituted of a smallnumber of lenses as described above, it is preferable that each of thesecond lens group through the fifth lens group has one or morenon-spherical surfaces.

[0026] According to another preferred embodiment of the presentinvention, a zoom lens includes a first lens group having a positiverefracting power, a second lens group having a negative power, a thirdlens group having a positive refracting power, a fourth lens grouphaving a positive refracting power, and a fifth lens group having apositive refracting power. The first lens group, the second group lens,the third lens group, the fourth lens group, and the fifth lens groupare arranged in succession. The zoom lens is configured such that whenzooming from a short focal length end toward a long focal length end, atleast a distance between the first lens group and the second lens groupincreases, and a distance between the second lens group and the thirdlens group and a distance between the third lens group and the fourthlens group decrease. When a distance from a first lens surface of thezoom lens to an imaging plane of the zoom lens at the long focal lengthend is Σd, an image height is y′, and a zooming ratio is Z, a followingcondition is satisfied: Σd/(Z×y′)<3.5.

[0027] A background zoom lens including five lens groups, a first lensgroup having a positive power, a second lens group having a negativepower, a third lens group having a positive power, a fourth lens grouphaving positive power, and a fifth lens group having a positive power,is configured such that when zooming, the first lens group, the thirdlens group, and fifth lens group are fixed, the second lens group ismoved, thereby zooming of the zoom lens being performed, and a shift inthe position of an imaging plane of the zoom lens associated with thezooming is corrected by moving the fourth lens group. Therefore, themoving amount of the second lens group for performing the zooming isrelatively large, and the first lens group must be arranged at a distantposition from an aperture diaphragm arranged in the third lens group, sothat the size of the first lens group is increased, thereby the overallsize of the zoom lens being increased.

[0028] The immediately above-described zoom lens of the presentinvention is configured such that when zooming the second lens groupmoves toward the third lens group and at the same time the fourth lensgroup moves toward the third lens group, thereby the zooming beingperformed, and a shift in the position of the imaging plane due tomovement of the second lens group and the fourth lens group is correctedby the fifth lens group. By configuring the zoom lens as above, aportion of the zooming is performed by the fourth group also, inaddition to the second lens group, and a shift in the position of theimaging plane due to the zooming is corrected by the fifth lens group.Thereby, the moving amount of the second lens group can be suppressedsmall and the distance of the first lens group from the aperturediaphragm can be reduced, so that the outer diameter of the first lensgroup can be made small and the overall size of the zoom lens can bereduced, and at the same time, by moving the fifth lens group, freedomin enhancing the performance of the zoom lens is increased, so thatenhancement of the performance can be achieved.

[0029] The above conditional formula specifies the overall size of thezoom lens, and if the upper limit is exceeded, the overall length of thezoom lens will increase, the outer diameter of the first lens group willincrease, the cost of the zoom lens will greatly increase, and the sizeof a camera apparatus using the zoom lens will increase.

[0030] In the immediately above-described zoom lens, the first lensgroup may be mounted at a fixed position. That is, the first lens groupmay be a fixed lens group that does not move when the zoom lens iszoomed and when a portion of lens groups moves for focusing. Forrealizing moving of moving lens groups of a zoom lens with a simplemechanism, it is preferable that the zoom lens is configured such thatthe first lens group is fixed. The first lens group has a largest outerdiameter among the lens groups constituting the zoom lens, andconsequently, the first lens group is relatively heavy. Accordingly, itis hard to realize moving of the first lens group with a simplemechanism and reduced power consumption. Further, if the zoom lens isconfigured such that focusing is performed by the first lens group, theperipheral light quantity at a short photographing distance is greatlyreduced as a result of movement of the first lens group, which isundesirable. For avoiding this disadvantage, the first lens group mustbe made extremely large. By configuring the zoom lens such that thefirst lens group is fixed as above, as might be expected, the distancefrom the first lens surface of the zoom lens to the imaging plane isconstant through the entire zooming range.

[0031] In the immediately above-described zoom lens, an aperturediaphragm may be arranged in the vicinity of the third lens group, andin particular, it is preferable that the aperture diaphragm is arrangedat a most outside position of the third lens group at a side of thesecond lens group. Further, it is preferable that the third lens groupincluding the aperture diaphragm is mounted at a fixed position.

[0032] Generally, a shutter is provided at the position of the aperturediaphragm. A mechanism for moving the shutter is relatively complicated.Further, if the shutter is moved, vibration at the time of driving theshutter tends to be transmitted to other parts of the zoom lens, causingdeterioration of the performance of the zoom lens, e.g. image burring.Thus, it is preferable that the third lens group including a shutter isnot moved.

[0033] The immediately above-described zoom lens may be configured suchthat when a focal length of the second lens group is f2, a synthesizedfocal length of the first lens group through the fifth lens group at theshort focal length end is fw, the following conditional formula issatisfied: 0.68<−f2/fw<2.0.

[0034] In the above conditional formula, −f2/fw specifies a range ofpower of the second lens group, and for reducing the overall size of thezoom lens, it is preferable that the above conditional formula issatisfied. If the upper limit is exceeded, the power of the second lensgroup will be excessively weak, the moving amount of the second lensgroup when the zoom lens is moved will increase, so that the overallsize of the zoom lens will not be reduced. If the lower limit isexceeded, contribution of the fourth lens group to a zooming functionwill be excessively small, so that the power of the first lens groupwill be excessively strong and aberration in the first lens group willbe excessively increased, and thereby satisfactory imaging performancewill not be obtained.

[0035] Further, the immediately above-described zoom lens may beconfigured such that focusing of the zoom lens is achieved by movementof the fifth lens group. Generally, the moving amount of a focusing lensgroup of a zoom lens when focusing on an object at a same photographingdistance is small at the short focal length end and is greater as thefocusing lens group is closer to the long focal length end. In theabove-described zoom lens of the present invention, the distance betweenthe fourth lens group and the fifth lens group is small at the shortfocal length end and is greater at the long focal length end.Accordingly, a space in which the fifth lens group is moved for focusingcan be obtained without interfering with the fourth lens group at anyzooming position. Further, the zoom lens of the present invention isconfigured such that a shift in the position of an imaging plane of thezoom lens involved in zooming the zoom lens is corrected by the fifthlens group. Therefore, the zoom lens of the present invention has anadvantage that a moving mechanism and a control mechanism for correctinga shift in the position of an imaging plane can be combined with thosemechanisms for focusing.

[0036] Furthermore, the immediately above-described zoom lens may beconfigured such that each of the first lens group and the second lensgroup includes three pieces of lens, the fourth lens group includesthree or four pieces of lens, and the fifth lens group includes onepiece of lens.

[0037] For obtaining a high performance zoom lens, each aberration mustbe suppressed small. For correcting each aberration satisfactorily, onemay increase the number of lenses constituting the zoom lens to acertain extent, and aberration in each lens must be suppressed small.However, if the number of lenses constituting the zoom lens increases,the thickness of each lens group increases, so that the overall size ofthe zoom lens cannot be reduced, and at the same time the constructionof the zoom lens is complicated and thereby the cost of the zoom lens isincreased.

[0038] Therefore, in the above-described zoom lens of the presentinvention, each of the first lens group and the second lens group isconstituted of a relatively small number of lenses, i.e., three piecesof lens, and the fourth lens group is constituted of three or fourpieces of lens for reducing an effect of deterioration in the imagingperformance due to decentering of each lens of the fourth lens group.Further, the fifth lens group is constituted of one piece of lens. Whenthe fifth lens group is moved for correcting a shift in the position ofan imaging plane and for focusing, because the number of lensesconstituting the fifth lens group is small and thereby the fifth lensgroup is light, the fifth lens group can be moved by less energy.

[0039] Furthermore, each of the first lens group through the third lensgroup may include one or more non-spherical surfaces. By configuring thezoom lens as described above, satisfactory imaging performance can bemaintained despite that the number of lenses constituting the zoom lensis relatively small.

[0040] Still further, the first lens group may be constituted of threepieces of lens, a negative lens and a first positive lens that arejoined, and a second positive lens. By configuring the first lens groupas above, color aberration of the first lens group can be suppressedsmall, and at the same time aberration at the positions outside of anoptical axe can be suppressed small and the field angle can be madewide. Still further, the second lens group may be constituted of threepieces of lens, a first negative lens, and a second negative lens and apositive lens that are joined. With this configuration of the secondlens group, aberration change of the second lens group when the zoomlens is zoomed can be suppressed small, color aberration of the secondlens group can be suppressed small, and deterioration of the imagingperformance due to decentering in the second lens group can be madesmall.

[0041] Each of the above-described zoom lenses of the present inventioncan be configured such that a diameter of an aperture diaphragm at thelong focal length end is greater than a diameter of an aperturediaphragm at the short focal length end.

[0042] In recent years, for achieving high quality of a recorded image,the technology of CCDs have greatly progressed in increasing theirresolutions, and a CCD having the total number of picture elements from3 millions to 4 millions has been materialized. In order to realize bothof increasing the resolution and decreasing the size of a CCD, the sizeof one picture element has been reduced. For example, the size of onepicture element of a 1/2.7 type CCD having the total number of pictureelements of 4 millions is extremely small, for example, about 2.8 μm. Azoom lens using a CCD in which the size of a picture element isextremely small as above must have a satisfactory imaging performance atan extremely high evaluation frequency such as 180 line/mm. At thistime, if the F number is dark, the imaging performance is decreasedbecause of an effect of diffraction even when no aberration exists inthe zoom lens. In each of the above-described zoom lenses of the presentinvention, by configuring the second lens group and the fourth lensgroup such that contribution to zooming of the zoom lens isappropriately shared, a change in the F number at the long focal lengthend from that at the short focal length end is suppressed small.However, in order to increase the performance at the long focal lengthend at a high evaluation frequency exceeding, for example, 180 line/mm,it is preferable that the F number at the long focal length end isbrighter. For this reason, in each of the above-described zoom lenses ofthe present invention, in order to increase the brightness at the longfocal length end, the diameter of the aperture diaphragm at the longfocal length end is greater than a diameter of an aperture diaphragm atthe short focal length end.

[0043] For further decreasing the size of the zoom lens, it ispreferable that the fourth lens group is constituted of four pieces oflens and the following two conditional formulas are satisfied:2.25<Σd/(Z×y′)<2.9 and 0.8<−f2/fw<1.45.

[0044] Each of the above-described zoom lenses can be used for a zoomlens for projection, for example, in a liquid crystal projector, etc. Inthis case, a liquid crystal as an object is arranged at the fifth lensgroup side and a light emerged from the first lens group side isenlarged and projected on a screen as an imaging plane.

[0045] Each of the above-described zoom lenses may be configured toserve as a photographing zoom lens with the first lens group arranged atthe side of an object. By arranging the first lens surface of the firstlens group at the side of an object, an image of the object can bereduced and imaged on a light receiving element such as a CCD, so that asatisfactory imaging performance can be obtained.

[0046] According to another preferred embodiment of the presentinvention, a camera apparatus using any one of the above-described zoomlenses for a photographing zoom lens is provided.

[0047] The camera apparatus may include a device for converting aphotographed image into digital information.

[0048] The camera apparatus records an image of an object via any one ofthe zooms lenses of the present invention configured to be used for aphotographing zoom lens. The camera apparatus may be practiced as asilver film camera using a silver film for a recording medium and adigital camera or a digital video camera in which an image of an objectis imaged on a light receiving element such as a CCD and information ofthe object is recorded as digital information. The camera apparatus thusrealized is extremely compact in size, has a high zooming ratio and ahigh image quality, and saves energy consumption.

[0049] The above-described camera may be configured such that a lightreceiving element receiving an image light of an object imaged by a zoomlens has the number of picture elements equal to or greater than 3millions. As the number of picture elements of a light receiving elementincreases, the density of recording an image of an object increases. Byusing a light receiving element having the number of picture elementsequal to or greater than 3 millions, the camera apparatus can obtain aphotographed image with such a quality that when the photographed imageis printed by a printer, the quality of the printed image is equal to orbetter than that of a photographed image photographed on a silver filmby a conventional silver film camera.

[0050] According to still another preferred embodiment of the presentinvention, a portable information terminal apparatus is provided. Theportable information terminal apparatus includes any of theabove-described camera apparatuses of the present invention and acommunication interface for transmitting via communication data recordedby the camera apparatus for example to a personal computer. By using anyof the above-described camera apparatuses of the present invention, theportable information terminal apparatus can be remarkably compact andcan obtain recorded data of high quality.

BRIEF DESCRIPTION OF THE DRAWINGS

[0051] A more complete appreciation of the present invention and many ofthe attendant advantages thereof will be readily obtained as the samebecomes better understood by reference to the following detaileddescription when considered in conjunction with accompanying drawings,wherein:

[0052]FIG. 1 is a diagram of a zoom lens according to a preferredembodiment of the present invention, illustrating a construction of thezoom lens and a positional relation of lens groups constituting the zoomlens at each zooming position;

[0053]FIG. 2 is a diagram for explaining movement of each lens group ofthe zoom lens when the zoom lens is zoomed;

[0054]FIG. 3 is a cross section illustrating a construction of a zoomlens of Example 1 of the embodiment and a positional relation of lensgroups constituting the zoom lens at each zooming position;

[0055]FIG. 4 is a cross section illustrating a construction of a zoomlens of Example 2 of the embodiment and a positional relation of lensgroups constituting the zoom lens at each zooming position;

[0056]FIG. 5 is a cross section illustrating a construction of a zoomlens of Example 3 of the embodiment and a positional relation of lensgroups constituting the zoom lens at each zooming position;

[0057]FIG. 6 is a cross section illustrating a construction of a zoomlens of Example 4 of the embodiment and a positional relation of lensgroups constituting the zoom lens at each zooming position;

[0058]FIG. 7 is a cross section illustrating a construction of a zoomlens of Example 5 of the embodiment and a positional relation of lensgroups constituting the zoom lens at each zooming position;

[0059]FIG. 8 is a cross section illustrating a construction of a zoomlens of Example 6 of the embodiment and a positional relation of lensgroups constituting the zoom lens at each zooming position;

[0060]FIG. 9 is a cross section illustrating a construction of a zoomlens of Example 7 of the embodiment and a positional relation of lensgroups constituting the zoom lens at each zooming position;

[0061]FIG. 10 is a cross section illustrating a construction of a zoomlens of Example 8 of the embodiment and a positional relation of lensgroups constituting the zoom lens at each zooming position;

[0062]FIG. 11 is a cross section illustrating a construction of a zoomlens of Example 9 of the embodiment and a positional relation of lensgroups constituting the zoom lens at each zooming position;

[0063]FIG. 12 is a cross section illustrating a construction of a zoomlens of Example 10 of the embodiment and a positional relation of lensgroups constituting the zoom lens at each zooming position;

[0064]FIG. 13 is a cross section illustrating a construction of a zoomlens of Example 11 of the embodiment and a positional relation of lensgroups constituting the zoom lens at each zooming position;

[0065]FIG. 14 is a diagram illustrating aberration curves at respectivezooming positions of the zoom lens of Example 1;

[0066]FIG. 15 is a diagram illustrating aberration curves at respectivezooming positions of the zoom lens of Example 2;

[0067]FIG. 16 is a diagram illustrating aberration curves at respectivezooming positions of the zoom lens of Example 3;

[0068]FIG. 17 is a diagram illustrating aberration curves at respectivezooming positions of the zoom lens of Example 4;

[0069]FIG. 18 is a diagram illustrating aberration curves at respectivezooming positions of the zoom lens of Example 5;

[0070]FIG. 19 is a diagram illustrating aberration curves at respectivezooming positions of the zoom lens of Example 6;

[0071]FIG. 20 is a diagram illustrating aberration curves at respectivezooming positions of the zoom lens of Example 7;

[0072]FIG. 21 is a diagram illustrating aberration curves at respectivezooming positions of the zoom lens of Example 8;

[0073]FIG. 22 is a diagram illustrating aberration curves at respectivezooming positions of the zoom lens of Example 9;

[0074]FIG. 23 is a diagram illustrating aberration curves at respectivezooming positions of the zoom lens of Example 10;

[0075]FIG. 24 is a diagram illustrating aberration curves at respectivezooming positions of the zoom lens of Example 11;

[0076]FIG. 25 is a diagram illustrating a concept of a digital camerausing a zoom lens of the present invention, according to an embodimentof the present invention;

[0077]FIG. 26 is a diagram illustrating an exemplary control system of aphotographing device of the digital camera, and a concept of a portableinformation terminal apparatus according to an embodiment of the presentinvention; and

[0078]FIG. 27 is a diagram illustrating a concept of a single lensreflex type camera using a zoom lens of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0079] Referring now to the drawings, wherein like reference numeralsdesignate identical of corresponding parts throughout the several views,preferred embodiment of the present invention are described.

[0080]FIG. 1 is a diagram of a zoom lens according to a preferredembodiment of the present invention, illustrating a construction of thezoom lens (of Example 8 of the embodiment) and a positional relation oflens groups constituting the zoom lens at each zooming position. FIG. 2is a diagram for explaining movement of each lens group of the zoom lenswhen the zoom lens is zoomed. FIG. 3 illustrates a construction of azoom lens of Example 1 of the embodiment and a positional relation oflens groups constituting the zoom lens at each zooming position. FIG. 4illustrates a construction of a zoom lens of Example 2 of the embodimentand a positional relation of lens groups constituting the zoom lens ateach zooming position. FIG. 5 illustrates a construction of a zoom lensof Example 3 of the embodiment and a positional relation of lens groupsconstituting the zoom lens at each zooming position. FIG. 6 illustratesa construction of a zoom lens of Example 4 of the embodiment and apositional relation of lens groups constituting the zoom lens at eachzooming position. FIG. 7 illustrates a construction of a zoom lens ofExample 5 of the embodiment and a positional relation of lens groupsconstituting the zoom lens at each zooming position. FIG. 8 illustratesa construction of a zoom lens of Example 6 of the embodiment and apositional relation of lens groups constituting the zoom lens at eachzooming position. FIG. 9 illustrates a construction of a zoom lens ofExample 7 of the embodiment and a positional relation of lens groupsconstituting the zoom lens at each zooming position. FIG. 10 illustratesa construction of a zoom lens of Example 8 of the embodiment and apositional relation of lens groups constituting the zoom lens at eachzooming position. FIG. 11 illustrates a construction of a zoom lens ofExample 9 of the embodiment and a positional relation of lens groupsconstituting the zoom lens at each zooming position. FIG. 12 illustratesa construction of a zoom lens of Example 10 of the embodiment and apositional relation of lens groups constituting the zoom lens at eachzooming position. FIG. 13 illustrates a construction of a zoom lens ofExample 11 of the embodiment and a positional relation of lens groupsconstituting the zoom lens at each zooming position. In FIG. 3 throughFIG. 13, symbol FI denotes a filter, symbol C denotes a CCD cover glass,and symbol K denotes an imaging plane.

[0081] Each of the zoom lenses of Example 1 through Example 9 includes afirst lens group G1 having a positive refracting power, a second lensgroup G2 having a negative refracting power, a third lens group G3having a positive refracting power, a fourth lens group G4 having apositive refracting power, and a fifth lens group G5 having a positiverefracting power. The first lens group G1, the second lens group G2, thethird lens group G3, the fourth lens group G4, and the fifth lens groupG5 are arranged in succession. Each of the zoom lenses is configuredsuch that when zooming from the short focal length end toward the longfocal length end, the second lens group G2 moves toward the third lensgroup G3 and the fourth lens group G4 moves toward the third lens groupG3, thereby performing the zooming. A shift in the position of theimaging plane K of the zoom lens due to movement of the second lensgroup G2 and the fourth lens group G4 is corrected by the fifth lensgroup G5. Further, when the distance from a first lens surface of thezoom lens at the long focal length end to the imaging plane K is Σd, asynthesized focal length of the first lens group G1 through the fifthlens group G5 at the short focal length end is fw, and a synthesizedfocal length of the first lens group G1 through the fifth lens group G5at the long focal length end is ft, a following conditional formula issatisfied: 1.45<Σd/(ft−fw)<2.2.

[0082] In each of the zoom lenses of Example 1 through Example 9, thefirst lens group G1 is mounted at a fixed position. Further, the thirdlens group G3 includes an aperture diaphragm S arranged at a mostoutside position at the side of the second lens group G2, and the thirdlens group G3 including the aperture diaphragm S is mounted at a fixedposition.

[0083] Further, each of the zoom lenses of Example 1 through Example 9is configured such that focusing of the zoom lens is achieved bymovement of the fifth lens group G5. Furthermore, each of the zoomlenses of Example 1 through Example 9 is configured such that the firstlens group G1 is positioned at the side of an object, so that the zoomlens can be used for a photographing zoom lens.

[0084] Each of the zoom lenses of Example 1 through Example 9 can bealso used for a zoom lens for projection in a liquid crystal projector.In this case, a liquid crystal display as an object is arranged at theimaging plane K at the side of the fifth lens group G5 and a radiatedlight from the side of the first lens group G1 is enlarged by the zoomlens and projected on a screen, etc., as an imaging plane.

[0085] Each of the zoom lenses of Example 1 through Example 9 isconfigured to satisfy, when a synthesized focal length of the first lensgroup G1 is f1 and a synthesized focal length of the first lens group G1and the second lens group G2 at the long focal length end is f12t, thefollowing conditional formula; −1.8<f12t/f1<−1.1.

[0086] Further, each of the zoom lenses of Example 1 through Example 9is configured to satisfy, when a distance between the first lens groupG1 and the second lens group G2 at the short focal length end is d1w, adistance between the first lens group G1 and the second lens group G2 atthe long focal length end is d1t, a distance between the third lensgroup G3 and the fourth lens group G4 at the short focal length end isd3w, and a distance between the third lens group G3 and the fourth lensgroup G4 at the long focal length end is d3t, the following conditionalformula; 0.3<(d3w−d3t)/(d1t−d1w)<0.8.

[0087] Each of the zoom lenses of Example 1 through Example 9 isconfigured such that the first lens group G1 includes three pieces oflens, a first lens L1, a second lens L2, and a third lens L3, the secondlens group G2 includes three pieces of lens, a fourth lens L4, a fifthlens L5, and a sixth lens L6, the third lens group G3 includes one pieceof lens, a seventh lens L7, the fourth lens group G4 includes fourpieces of lens, an eighth lens L8, a ninth lens L9, a tenth lens L10,and an eleventh lens L11, the fifth lens group G5 includes one piece oflens, a twelfth lens L12, and each of the second lens group G2 throughthe fifth lens group G5 includes one or more non-spherical surfaces.

[0088] Further, each of the zoom lenses of Example 1 through Example 9can be configured such that the diameter of the aperture diaphragm S atthe long focal length end is greater than a diameter of an aperturediaphragm at the short focal length end. In this case, the diameter ofthe aperture diaphragm S may be coupled with a zooming mechanism.

[0089] Now, the zoom lenses of Example 1 through Example 9 aredescribed.

[0090] Here, symbol R denotes a radius of curvature of each surface oflenses, or a paraxial radius of curvature when the surface isnon-spherical. Symbol D denotes a distance between surfaces of lenses.Symbol Nd denotes a refractive index for a “d” line, and symbol Vddenotes the Abbe number for the d line. Symbol f denotes a synthesizedfocal length of an entire system of a zoom lens. Symbol F denotes a Fnumber. Symbol ω denotes a half field angle. Symbol y′ denotes an imageheight. Symbol “Wide” denotes a short focal length end, symbol “Mean”denotes a middle focal length, and symbol “Wide” denotes a long focallength end.

[0091] Further, the shape of a non-spherical surface is expressed by thefollowing formula;X=[{(1/R)×Y2}/{1+SQRT(1−(1+K)×(Y/R)2)}]+A4×Y4+A6×Y6+A8×Y8+A10×Y10. Here,symbol X represents a distance from a tangent plane at a peak of anon-spherical surface at a height Y from an optical axis, symbol Yrepresents a height from the optical axis, symbol R represents aparaxial radius of curvature of a non-spherical surface, and symbol Krepresents a cone multiplier factor, A4, A6, A8, and A10 representnon-spherical surface coefficients, and SQRPT indicates a square root.Further, in the following Tables, E-XY means 10-XY, and N denotessurface number.

[0092]FIG. 14 through FIG. 24 illustrate aberration curves with respectto Example 1 through Example 11, respectively. In these figures, symbolSA denotes a spherical aberration and symbol SC denotes a sinecondition, and a solid line illustrates a spherical aberration and adotted line indicates a sine condition. Symbol Ast denotes anastigmatism, and a solid line indicates an astigmatism in a sagittalplane and a dotted line indicates an astigmatism in a meridional plane.Symbol D is denotes a distortion aberration and symbol Coma denotes acoma. Symbol d denotes a d line (587.56 nm), and symbol g denotes a gline (435.83 nm). Symbols of a d line and a g line are shown in figureat the long focal length end only with respect to the sphericalaberration and the astigmatism, and at the short focal length end onlywith respect to the coma. In Example 1 through Example 11, the imageheight y′ is 4.65 mm.

EXAMPLE 1

[0093] TABLE 1 f = 5.799˜38.111, F = 2.610˜3.973, ω = 31.113˜5.247 N R DNd Vd Note 1 43.041 1.200 1.84666 23.8 First lens 2 19.038 3.311 1.4874970.4 Second lens 3 −141.582 0.100 4 20.219 2.140 1.80420 46.5 Third lens5 174.024 d1(variable) 6 −28.196 0.040 1.51940 52.1 Non-sphericalsurface resin layer 7 −38.550 0.800 1.76200 40.3 Fourth lens 8 6.6101.799 9 −14.056 0.800 1.48749 70.4 Fifth lens 10 8.564 1.702 1.8466623.8 Sixth lens 11 54.745 d2(variable) 12 diaphragm 1.000 13 9.741 0.0401.51940 52.1 Non-spherical surface resin layer 14 9.797 1.148 1.5891361.3 Seventh lens 15 14.533 d3(variable) 16 7.868 0.080 1.51940 52.1Non-spherical surface resin layer 17 8.385 2.889 1.48749 70.4 Eighthlens 18 −28.071 0.100 19 19.185 0.040 1.51940 52.1 Non-spherical surfaceresin layer 20 27.029 1.733 1.58913 61.3 Ninth lens 21 −27.646 0.100 2217.156 1.285 1.67270 32.2 Tenth lens 23 35.334 0.800 1.84666 23.8Eleventh lens 24 5.477 d4(variable) 25 10.730 1.988 1.48749 70.4 Twelfthlens 26 −56.429 0.040 1.51940 52.1 Non-spherical surface resin layer 27−81.532 d5(variable) 28 0.0 0.927 1.54892 69.3 Filter 29 0.0 0.800 300.0 0.500 1.50000 64.0 CCD cover glass 31 0.0 0.99

[0094] TABLE 2 non-spherical surface coefficient: N K A4 A6 A8 A10 6 0.02.47529E−04 −3.50886E−06 7.03335E−08 −7.84536E−10   13 −2.946422.55415E−04 −8.63166E−06 7.23626E−07 −3.09544E−08   16 −1.033152.11610E−05   3.63732E−06 −1.37529E−07   9.73975E−10 19 −12.59912−1.51880E−04   −7.71000E−06 1.89496E−07 1.91522E−10 27 0.0−1.21598E−04   −2.05635E−06 5.32282E−08 6.57147E−10

[0095] TABLE 3 variable distance: f d1 d2 d3 d4 d5 Wide 5.799 1.43512.196 7.251 3.870 2.886 Mean 14.804 7.345 6.286 2.686 7.768 3.552 Tele38.111 12.581 1.051 1.010 11.253 1.744

[0096] TABLE 4 parameter values of the conditional formula: Σd/(ft − fw)1.671 f12t/f1 −1.635 (d3w − d3t)/(d1t − d1w) 0.560 Σd/(Z × y′) 2.348−f2/fw 1.143

[0097] The construction of the zoom lens of Example 1 is illustrated inFIG. 3, and the aberration curves are illustrated in FIG. 14.

EXAMPLE 2

[0098] TABLE 5 f = 5.496˜31.029, F = 2.630˜3.910, ω = 32.489˜6.436 N R DNd Vd Note 1 31.327 1.200 1.84666 23.8 First lens 2 17.125 3.083 1.4874970.4 Second lens 3 177.033 0.100 4 21.600 2.134 1.80420 46.5 Third lens5 255.462 d1(variable) 6 −20.730 0.040 1.51940 52.1 Non-sphericalsurface resin layer 7 −31.238 0.800 1.80610 33.3 Fourth lens 8 6.7091.904 9 −12.180 0.800 1.48749 70.4 Fifth lens 10 10.480 1.805 1.8466623.8 Sixth lens 11 −64.972 d2(variable) 12 diaphragm 1.000 13 11.1320.040 1.51940 52.1 Non-spherical surface resin layer 14 11.064 1.1291.58913 61.3 Seventh lens 15 17.841 d3(variable) 16 8.034 0.080 1.5194052.1 Non-spherical surface resin layer 17 8.803 2.757 1.48749 70.4Eighth lens 18 −23.535 0.489 19 19.515 0.040 1.51940 52.1 Non-sphericalsurface resin layer 20 22.991 1.715 1.58913 61.3 Ninth lens 21 −30.4630.100 22 15.964 1.408 1.64769 33.8 Tenth lens 23 71.516 0.800 1.8466623.8 Eleventh lens 24 5.155 d4(variable) 25 10.168 2.216 1.48749 70.4Twelfth lens 26 −30.672 0.040 1.51940 52.1 Non-spherical surface resinlayer 27 −37.562 d5(variable) 28 0.0 0.927 1.54892 69.3 Filter 29 0.00.800 30 0.0 0.500 1.50000 64.0 CCD cover glass 31 0.0 0.990

[0099] TABLE 6 non-spherical surface coefficient: N K A4 A6 A8 A10 60.00000   4.52605E−04 −6.88402E−06 1.17635E−07 −1.12305E−09 13 −3.48618  2.15747E−04 −1.09049E−05 1.31234E−06 −6.96078E−08 16 −1.18470−1.54271E−05   1.52593E−06 −1.63490E−07     9.46817E−10 19 −10.36925−1.14874E−04 −4.06197E−06 2.81367E−07 −6.45640E−10 27 0.00000−1.36885E−04 −4.79430E−06 2.58969E−07 −4.22551E−09

[0100] TABLE 7 variable distance: f d1 d2 d3 d4 d5 Wide 5.496 1.47612.182 7.287 2.499 2.659 Mean 13.193 7.030 6.629 2.468 7.461 2.515 Tele31.029 12.668 0.990 1.010 9.022 2.413

[0101] TABLE 8 parameter values of the conditional formula: Σd/(ft − fw)2.076 f12t/f1 −1.396 (d3w − d3t)/(d1t − d1w) 0.561 Σd/(Z × y′) 2.682−f2/fw 1.305

[0102] The construction of the zoom lens of Example 2 is illustrated inFIG. 4, and the aberration curves are illustrated in FIG. 15.

EXAMPLE 3

[0103] TABLE 9 f = 5.919˜33.448, F = 2.893˜3.342, ω = 30.597˜5.974 N R DNd Vd Note 1 26.775 1.200 1.84666 23.8 First lens 2 17.574 3.074 1.4874970.4 Second lens 3 185.582 0.100 4 25.927 2.080 1.72916 54.7 Third lens5 229.083 d1(variable) 6 −31.934 0.040 1.51940 52.1 Non-sphericalsurface resin layer 7 −45.433 0.800 1.80610 33.3 Fourth lens 8 7.1982.003 9 −12.589 0.800 1.48749 70.4 Fifth lens 10 10.383 1.818 1.8466623.8 Sixth lens 11 −129.968 d2(variable) 12 diaphragm 1.000 13 12.1240.040 1.51940 52.1 Non-spherical surface resin layer 14 12.016 1.2641.48749 70.4 Seventh lens 15 33.618 d3(variable) 16 8.250 0.040 1.5194052.1 Non-spherical surface resin layer 17 8.301 2.730 1.48749 70.4Eighth lens 18 −51.352 0.388 19 22.209 1.771 1.58313 59.5 Ninth lens 20−18.512 0.100 21 121.290 2.306 1.77250 49.6 Tenth lens 22 −12.334 0.8001.71736 29.5 Eleventh lens 23 5.530 d4(variable) 24 9.624 0.040 1.5194052.1 Non-spherical surface resin layer 25 9.255 2.595 1.51823 59.0Twelfth lens 26 −68.652 d5(variable) 27 0.000 0.927 1.54892 69.3 Filter28 0.0 0.800 29 0.0 0.500 1.50000 64.0 CCD cover glass 30 0.0 0.990

[0104] TABLE 10 non-spherical surface coefficient: N K A4 A6 A8 A10 60.00000 2.06128E−04 −9.12096E−07 −4.30561E−08 1.09813E−09 13 −3.989501.89732E−04 −6.50497E−06   5.10027E−07 −1.95031E−08   16 −0.643948.51623E−05   1.80838E−06 −2.98161E−08 2.28622E−09 19 −28.48660−1.01774E−04   −1.04454E−05   1.60236E−07 −3.04227E−09   24 −0.036397.11396E−05   7.22409E−06 −4.57801E−07 1.20054E−08

[0105] TABLE 11 variable distance: f d1 d2 d3 d4 d5 Wide 5.919 1.38313.898 6.684 2.501 2.327 Mean 13.989 7.918 7.363 2.189 7.080 2.244 Tele33.448 14.291 0.990 1.010 8.758 1.745

[0106] TABLE 12 parameter values of the conditional formula: Σd/(ft −fw) 1.998 f12t/f1 −1.467 (d3w − d3t)/(d1t − d1w) 0.440 Σd/(Z × y′) 2.781−f2/fw 1.323

[0107] The construction of the zoom lens of Example 3 is illustrated inFIG. 5, and the ration curves are illustrated in FIG. 16.

EXAMPLE 4

[0108] TABLE 13 f = 7.595˜35.700, F = 2.704˜3.709, ω = 31.476˜7.421 N RD Nd Vd Note 1 32.055 1.200 1.84666 23.8 First lens 2 15.924 3.3801.48749 70.4 Second lens 3 119.270 0.100 4 19.177 2.564 1.83500 43.0Third lens 5 189.651 d1(variable) 6 −49.582 0.040 1.51940 52.1Non-spherical surface resin layer 7 −76.252 0.800 1.83400 37.3 Fourthlens 8 6.907 1.912 9 −12.244 0.800 1.48749 70.4 Fifth lens 10 9.7241.642 1.84666 23.8 Sixth lens 11 210.552 d2(variable) 12 diaphragm 1.00013 12.252 0.040 1.51940 52.1 Non-spherical surface resin layer 14 12.3611.327 1.48749 70.4 Seventh lens 15 51.633 d3(variable) 16 8.443 0.0801.51940 52.1 Non-spherical surface resin layer 17 8.130 2.634 1.4874970.4 Eighth lens 18 −3715.338 0.100 19 16.423 2.141 1.58913 61.3 Ninthlens 20 −12.735 0.100 21 176.172 2.413 1.73400 51.1 Tenth lens 22 −6.8820.815 1.80610 33.3 Eleventh lens 23 6.309 d4(variable) 24 12.715 0.0401.51940 52.1 Non-spherical surface resin layer 25 11.978 2.493 1.5174252.2 Twelfth lens 26 −61.960 d5(variable) 27 0.000 0.927 1.54892 69.3Filter 28 0.0 0.800 29 0.0 0.500 1.50000 64.0 CCD cover glass 30 0.00.990

[0109] TABLE 14 non-spherical surface coefficient: N K A4 A6 A8 A10 60.00000 1.63442E−04 −1.36224E−06 −1.65713E−08 7.89957E−10 13 −3.130641.01247E−04 −3.91250E−06   5.13542E−07 −1.08121E−08   16 −0.294731.62021E−04   1.18078E−06 −1.42046E−07 6.10836E−09 19 −13.82162−2.73543E−04   −1.26291E−05   3.30630E−07 −7.50756E−09   24 0.078256.58815E−05   2.62084E−06 −7.92326E−08 1.21465E−09

[0110] TABLE 15 variable distance: f d1 d2 d3 d4 d5 Wide 7.595 1.28310.869 6.509 4.148 2.393 Mean 16.138 6.437 5.715 2.903 7.089 3.058 Tele35.700 11.142 1.009 1.010 10.288 1.752

[0111] TABLE 16 parameter values of the conditional formula: Σd/(ft −fw) 1.921 f12t/f1 −1.389 (d3w − d3t)/(d1t − d1w) 0.558 Σd/(Z × y′) 2.471−f2/fw 0.927

[0112] The construction of the zoom lens of Example 4 is illustrated inFIG. 6, and the aberration curves are illustrated in FIG. 17.

EXAMPLE 5

[0113] TABLE 17 f = 7.170˜33.688, F = 2.737˜3.871, ω = 32.966˜7.859 N RD Nd Vd Note 1 130.503 1.200 1.84666 23.8 First lens 2 23.226 2.8371.48749 70.4 Second lens 3 −404.423 0.100 4 18.852 0.040 1.51940 52.1Non-spherical surface resin layer 5 19.175 2.805 1.83500 43.0 Third lens6 −350.917 d1(variable) 7 −104.258 0.040 1.51940 52.1 Non-sphericalsurface resin layer 8 −241.841 0.800 1.83400 37.3 Fourth lens 9 6.8812.047 10 −11.080 0.0800 1.48749 70.4 Fifth lens 11 10.353 1.685 1.8466623.8 Sixth lens 12 0.000 d2(variable) 13 diaphragm 1.000 14 12.255 0.0401.51940 52.1 Non-spherical surface resin layer 15 8.764 1.569 1.4874970.4 Seventh lens 16 84.710 d3(variable) 17 8.306 2.796 1.48749 70.4Eighth lens 18 −72.425 0.256 19 20.256 2.130 1.58913 61.3 Ninth lens 20−12.766 0.100 21 −131.946 2.561 1.73400 51.1 Tenth lens 22 −6.707 0.8001.80610 33.3 Eleventh lens 23 6.320 d4(variable) 24 12.674 0.080 1.5194052.1 Non-spherical surface resin layer 25 11.936 2.423 1.51742 52.2Twelfth lens 26 −73.067 d5(variable) 27 0.000 0.927 1.54892 69.3 Filter28 0.0 0.800 29 0.0 0.500 1.50000 64.0 CCD cover glass 30 0.0 0.990

[0114] TABLE 18 non-spherical surface coefficient: N K A4 A6 A8 A10 4−0.32043 −8.87884E−06   −1.14685E−08 −3.39906E−10   2.05579E−12 70.00000 1.48773E−04 −3.74802E−06   9.59504E−08 −1.34029E−09 14 −2.955531.07483E−04 −3.82108E−06   3.20149E−07 −1.19761E−08 19 −21.71796−2.76275E−04   −1.31731E−05   1.89378E−07 −4.94556E−09 20 −0.038299.21558E−06 −2.59936E−06 −1.88757E−07 −7.95035E−10 24 0.012056.85989E−05   2.41929E−06  −8.7989E−08   1.29775E−09

[0115] TABLE 19 variable distance: f d1 d2 d3 d4 d5 Wide 7.170 1.00011.073 7.267 2.638 2.897 Mean 16.947 6.617 5.456 3.242 6.303 3.257 Tele33.688 11.083 1.010 1.010 10.044 1.748

[0116] TABLE 20 parameter values of the conditional formula: Σd/(ft −fw) 2.036 f12t/f1 −1.324 (d3w − d3t)/(d1t − d1w) 0.621 Σd/(Z × y′) 2.471−f2/fw 1.024

[0117] The construction of the zoom lens of Example 5 is illustrated inFIG. 7, and the aberration curves are illustrated in FIG. 18.

EXAMPLE 6

[0118] TABLE 21 f = 7.350˜34.568, F = 2.752˜3.861, ω = 32.319˜7.661 N RD Nd Vd Note 1 75.201 1.200 1.84666 23.8 First lens 2 25.353 2.2611.62041 60.3 Second lens 3 106.637 0.100 4 19.454 0.040 1.51940 52.1Non-spherical surface resin layer 5 19.967 2.753 1.72916 54.7 Third lens6 −144.880 d1(variable) 7 −101.235 0.040 1.51940 52.1 Non-sphericalsurface resin layer 8 −159.978 0.800 1.83400 37.3 Fourth lens 9 6.8832.324 10 −12.356 0.800 1.48749 70.4 Fifth lens 11 9.176 1.806 1.8051825.5 Sixth lens 12 564.525 d2(variable) 13 diaphragm 1.000 14 17.7980.040 1.51940 52.1 Non-spherical surface resin layer 15 17.361 1.2171.48749 70.4 Seventh lens 16 106.313 d3(variable) 17 8.660 0.040 1.5194052.1 Non-spherical surface resin layer 18 9.600 2.651 1.48749 70.4Eighth lens 19 −61.154 0.100 20 14.254 2.704 1.58913 61.3 Ninth lens 21−12.070 0.100 22 −68.163 2.130 1.77250 49.6 Tenth lens 23 −7.650 0.8001.80610 33.3 Eleventh lens 24 5.772 d4(variable) 25 12.018 0.080 1.5194052.1 Non-spherical surface resin layer 26 11.290 2.856 1.48749 70.4Twelfth lens 27 −36.271 d5(variable) 28 0.0 0.927 1.54892 69.3 Filter 290.0 0.800 30 0.0 0.500 1.50000 64.0 CCD cover glass 31 0.0 0.990

[0119] TABLE 22 non-spherical surface coefficient: N K A4 A6 A8 A10 4−0.35429 −9.11747E−06   −6.29514E−08   4.31692E−10 −2.93982E−12   70.00000 9.05116E−05 −1.72172E−06   2.31258E−08 −2.95845E−10   14−3.94910 6.95288E−05 −5.39196E−06   3.34741E−07 −8.93753E−09   17−1.05943 −6.86900E−07     9.45894E−07 −1.59002E−07 1.20429E−09 20−2.10346  −5.0281E−05     2.48786E−06  −2.4259E−08 3.14395E−09 21−4.43306 0.000105935  −2.411E−07  −1.3786E−07 3.94068E−09 25 −0.027298.55632E−05   2.14341E−06 −1.06558E−07 1.59037E−09

[0120] TABLE 23 variable distance: f d1 d2 d3 d4 d5 Wide 7.350 1.00011.250 6.820 4.618 2.252 Mean 16.172 6.115 6.135 2.251 8.827 2.612 Tele34.568 11.262 0.988 1.019 10.512 2.159

[0121] TABLE 24 parameter values of the conditional formula: Σd/(ft −fw) 2.021 f12t/f1 −1.392 (d3w − d3t)/(d1t − d1w) 0.565 Σd/(Z × y′) 2.515−f2/fw 1.017

[0122] The construction of the zoom lens of Example 6 is illustrated inFIG. 8, and the aberration curves are illustrated in FIG. 19.

EXAMPLE 7

[0123] TABLE 25 f = 7.723˜36.282, F = 2.797˜3.898, ω = 31.053˜7.303 N RD Nd Vd Note 1 49.797 1.200 1.84666 23.8 First lens 2 21.817 2.2191.62041 60.3 Second lens 3 62.402 0.100 4 19.435 0.040 1.51940 52.1Non-spherical surface resin layer 5 19.853 2.807 1.72916 54.7 Third lens6 −158.545 d1(variable) 7 −83.516 0.040 1.51940 52.1 Non-sphericalsurface resin layer 8 −125.642 0.800 1.83400 37.3 Fourth lens 9 7.0502.394 10 −13.304 0.800 1.48749 70.4 Fifth lens 11 9.248 1.862 1.8051825.5 Sixth lens 12 275.529 d2(variable) 13 diaphragm 1.000 14 87.5930.040 1.51940 52.1 Non-spherical surface resin layer 15 18.156 1.2341.48749 70.4 Seventh lens 16 160.349 d3(variable) 17 8.518 0.040 1.5194052.1 Non-spherical surface resin layer 18 9.215 2.866 1.48749 70.4Eighth lens 19 −57.466 0.100 20 14.144 2.646 1.58913 61.3 Ninth lens 21−13.070 0.100 22 −55.638 2.061 1.77250 49.6 Tenth lens 23 −8.222 0.8021.80610 33.3 Eleventh lens 24 5.896 d4(variable) 25 12.020 0.080 1.5194052.1 Non-spherical surface resin layer 26 11.383 3.683 1.48749 70.4Twelfth lens 27 −37.631 d5(variable) 28 0.0 0.927 1.54892 69.3 Filter 290.0 0.800 30 0.0 0.500 1.50000 64.0 CCD cover glass 31 0.0 0.990

[0124] TABLE 26 non-spherical surface coefficient: N K A4 A6 A8 A10 4−0.33625 −8.10669E−06   −5.99060E−08   3.80716E−10 −2.34989E−12   70.00000 1.02368E−04 −2.44629E−06   5.29615E−08 −6.57833E−10   14−4.85445 6.35848E−05  −5.5302E−07  −1.8991E−07 1.07493E−08 17 −1.067622.27487E−06   2.35789E−06  −7.205E−08 7.52775E−10 21 −7.331601.52640E−04 −1.13419E−06 −4.45159E−08 6.89536E−10 25 −0.154998.66173E−05   1.63737E−06 −9.85262E−08 1.62684E−09

[0125] TABLE 27 variable distance: f d1 d2 d3 d4 d5 Wide 7.723 1.00011.329 6.736 4.212 2.345 Mean 15.069 5.893 6.435 2.544 7.923 2.825 Tele36.282 11.323 1.006 1.010 10.547 1.736

[0126] TABLE 28 parameter values of the conditional formula: Σd/(ft −fw) 1.952 f12t/f1 −1.477 (d3w − d3t)/(d1t − d1w) 0.555 Σd/(Z x y’) 2.552−f2/fw 0.983

[0127] The construction of the zoom lens of Example 7 is illustrated inFIG. 9, and the ration curves are illustrated in FIG. 20.

EXAMPLE 8

[0128] TABLE 29 f = 7.435˜34.930, F = 2.806˜4.025, ω = 32.023˜7.583 N RD Nd Vd Note 1 39.039 1.200 1.84666 23.8 First lens 2 19.608 2.1861.62041 60.3 Second lens 3 38.055 0.100 4 19.092 0.040 1.51940 52.1Non-spherical surface resin layer 5 19.621 2.992 1.72916 54.7 Third lens6 −139.892 d1(variable) 7 −59.538 0.040 1.51940 52.1 Non-sphericalsurface resin layer 8 −90.088 0.800 1.83400 37.3 Fourth lens 9 7.2882.427 10 −14.597 0.835 1.48749 70.4 Fifth lens 11 9.669 1.897 1.8051825.5 Sixth lens 12 −30287.998 d2(variable) 13 Diaphragm 1.000 14 13.4420.040 1.51940 52.1 Non-spherical surface resin layer 15 13.284 1.1541.48749 70.4 Seventh lens 16 24.525 d3(variable) 17 8.750 2.923 1.4874970.4 Eighth lens 18 −29.084 0.100 19 15.202 2.490 1.58913 61.3 Ninthlens 20 −14.402 0.100 21 −66.558 2.049 1.77250 49.6 Tenth lens 22 −8.3501.542 1.80610 33.3 Eleventh lens 23 5.887 d4(variable) 24 11.590 0.0801.51940 52.1 Non-spherical surface resin layer 25 10.967 3.295 1.4874970.4 Twelfth lens 26 −41.067 d5(variable) 27 0.000 0.927 1.54892 69.3Filter 28 0.0 0.800 29 0.0 0.500 1.50000 64.0 CCD cover glass 30 0.00.990

[0129] TABLE 30 non-spherical surface coefficient: N K A4 A6 A8 A10 4−0.33840 −8.16702E−06 −6.83542E−08   5.01190E−10 −2.99601E−12   70.00000 0.000135267  −2.9502E−06   6.64739E−08  −7.9286E−10   14−3.13741 0.000103101  −1.7393E−06  −6.7796E−08 6.72154E−09 17 −1.23838−2.90971E−05   1.99782E−06 −7.63156E−08 8.21115E−10 20 −7.69343  1.34716E−04 −1.11390E−06 −4.77502E−08 7.36021E−10 24 −0.12190  9.12560E−05   2.41138E−06 −1.39770E−07 2.43613E−09

[0130] TABLE 31 variable distance: f d1 d2 d3 d4 d5 Wide 7.435 1.00011.605 6.554 3.705 2.129 Mean 15.965 6.285 6.320 2.573 7.148 2.667 Tele34.930 11.615 0.990 1.010 9.646 1.732

[0131] TABLE 32 parameter values of the conditional formula: Σd/(ft −fw) 2.019 f12t/f1 −1.451 (d3w − d3t)/(d1t − d1w) 0.522 Σd/(Z × y′) 2.541−f2/fw 1.078

[0132] The construction of the zoom lens of Example 8 is illustrated inFIG. 10, and the aberration curves are illustrated in FIG. 21.

EXAMPLE 9

[0133] TABLE 33 f = 5.847˜29.235, F = 2.797˜3.685, ω = 38.49˜9.04 N R DNd Vd Note 1 116.295 2.000 1.75677 32.3 First lens 2 32.400 3.6171.48700 70.4 Second lens 3 90.213 0.100 4 21.604 5.493 1.57081 63.2Third lens 5 −191.613 d1(variable) 6 −117.926 0.800 1.80386 37.0 Fourthlens 7 8.531 4.472 8 −15.502 0.800 1.48700 70.4 Fifth lens 9 18.0072.360 1.84700 23.8 Sixth lens 10 −78.902 d2(variable) 11 0.000 1.000 1210.432 0.040 1.51940 52.1 Non-spherical surface resin layer 13 9.4341.227 1.54292 65.2 Seventh lens 14 16.887 d3(variable) 15 22.010 6.8171.48700 70.4 Eighth lens 16 −18.362 0.100 17 23.596 1.410 1.69304 54.1Ninth lens 18 184.808 0.100 19 11.785 2.577 1.48700 70.4 Tenth lens 20−14.867 4.109 1.84191 29.3 Eleventh lens 21 8.572 d4(variable) 22 10.3003.292 1.74803 50.8 Twelfth lens 23 29.834 d5(variable) 24 0.000 0.9271.54892 69.3 Filter 25 0.000 0.800 26 0.000 0.500 1.50000 64.0 CCD coverglass 27 0.000 0.000

[0134] TABLE 34 non-spherical surface coefficient: N K A4 A6 A8 A10 4−0.19853 −6.52478E−06   −7.50313E−09 −3.47208E−11     4.04015E−14 662.83109 1.15620E−04 −8.97499E−07 6.63622E−09 −2.86861E−11 12 −2.486281.44484E−04 −6.75823E−07 4.55433E−09 −7.16329E−10

[0135] TABLE 35 variable distance: f d1 d2 d3 d4 d5 Wide 5.847 1.00019.676 7.347 1.419 2.037 Mean 12.979 10.426 10.270 2.732 5.671 2.385Tele 29.235 19.656 1.000 1.040 4.167 5.592

[0136] TABLE 36 parameter values of the conditional formula: Σd/(Z × y′)3.226 −f2/fw 1.740

[0137] The construction of the zoom lens of Example 9 is illustrated inFIG. 11, and the aberration curves are illustrated in FIG. 22.

EXAMPLE 10

[0138] TABLE 37 f = 6.030˜30.148, F = 2.791˜3.656, ω = 37.64˜8.77, y′ =4.65 N R D Nd Vd Note 1 63.803 2.000 1.81097 31.0 First lens 2 28.8763.365 1.48700 70.4 Second lens 3 54.576 0.100 4 20.848 5.634 1.5871262.1 Third lens 5 −294.613 d1(variable) 6 −131.646 0.800 1.81166 36.3Fourth lens 7 8.490 4.482 8 −18.706 0.800 1,48700 70.4 Fifth lens 915.586 2.468 1.84700 23.8 Sixth lens 10 −171.904 d2(variable) 11 0.0001.000 12 11.383 0.040 1.51940 52.1 Non-spherical surface resin layer 1311.291 1.212 1.48700 70.4 Seventh lens 14 24.245 d3(variable) 15 32.1357.377 1.82467 43.9 Eighth lens 16 −19.362 0.100 17 11.704 2.690 1.5033368.7 Ninth lens 18 −12.781 5.315 1.84457 26.1 Tenth lens 19 9.069d4(variable) 20 10.021 3.594 1.77300 49.6 Eleventh lens 21 33.303d5(variable) 22 0.000 0.927 1.54892 69.3 Filter 23 0.000 0.800 24 0.0000.500 1.50000 64.0 CCD cover glass 25 0.000 0.990

[0139] TABLE 38 non-spherical surface coefficient: N K A4 A6 A8 A10 4−0.18390 −5.93384E−06 −8.25984E−09 −2.66810E−11 −1.57227E−15 6 78.74298  9.99536E−05 −7.18770E−07   4.98815E−09 −1.99274E−11 12 −2.90185  1.20528E−04   2.21640E−06 −4.04302E−07   1.94453E−08

[0140] TABLE 39 variable distance: f d1 d2 d3 d4 d5 Wide 6.030 1.00019.282 7.625 0.910 2.002 Mean 13.401 10.330 9.971 2.939 5.322 2.259 Tele30.148 19.282 1.000 1.029 5.345 4.153

[0141] TABLE 40 parameter values of the conditional formula: Σd/(Z × y′)3.226 −f2/fw 1.722

[0142] The construction of the zoom lens of Example 10 is illustrated inFIG. 12, and the aberration curves are illustrated in FIG. 23.

[0143] In the zoom lenses of Example 1 through Example 10, two types ofnon-spherical surface are used, a so-called hybrid non-spherical surfacewhich is formed by providing a thin resin layer onto a glass lens so asto be formed in a non-spherical shape, and a so-called glassnon-spherical surface in which a surface of a glass lens itself isformed in a non-spherical shape. It is needless to say that any type ofnon-spherical surface may be used in the zoom lenses of the presentinvention so long as a non-spherical surface effect can be obtained. Inthe zoom lenses of Example 1 through Example 10, each hybridnon-spherical surface can be changed to a glass non-spherical surface,and vice versa.

[0144] The following Example 11 illustrates a zoom lens of Example 8 inwhich the hybrid non-spherical surface of the twelfth lens has beenchanged to a glass non-spherical surface.

EXAMPLE 11

[0145] TABLE 41 f = 7.406˜34.806, F = 2.793˜4.014, ω = 32.123˜7.610 N RD Nd Vd Note 1 39.039 1.200 1.84666 23.8 First lens 2 19.608 2.1861.62041 60.3 Second lens 3 38.055 0.100 4 19.092 0.040 1.51940 52.1Non-spherical surface resin layer 5 19.621 2.992 1.72916 54.7 Third lens6 −139.892 d1(variable) 7 −59.538 0.040 1.51940 52.1 Non-sphericalsurface resin layer 8 −90.088 0.800 1.83400 37.3 Fourth lens 9 7.2882.427 10 −14.597 0.835 1.48749 70.4 Fifth lens 11 9.669 1.897 1.8051825.5 Sixth lens 12 −30287.998 d2(variable) 13 Diaphragm 1.000 14 13.4420.040 1.51940 52.1 Non-spherical surface resin layer 15 13.284 1.1541.48749 70.4 Seventh lens 16 24.525 d3(variable) 17 8.750 2.923 1.4874970.4 Eighth lens 18 −29.084 0.100 19 15.202 2.490 1.58913 61.3 Ninthlens 20 −14.402 0.100 21 −66.558 2.049 1.77250 49.6 Tenth lens 22 −8.3501.542 1.80610 33.3 Eleventh lens 23 5.887 d4(variable) 24 11.708 3.4891.48749 70.4 Twelfth lens 25 −39.832 d5(variable) 26 0.000 0.827 1.6489269.3 Filter 27 0.0 0.800 28 0.0 0.500 1,50000 64.0 CCD cover glass 290.0 0.990

[0146] TABLE 42 non-spherical surface coefficient: N K A4 A6 A8 A10 4−0.33840 −8.16702E−06 −6.83542E−08   5.01190E−10 −2.99601E−12 7 0.000000.000135267  −2.9502E−06   6.64739E−08  −7.9286E−10 14 −3.137410.000103101  −1.7393E−06  −6.7796E−08   6.72154E−09 17 −1.23838−2.90971E−05   1.99782E−06 −7.63156E−08   8.21115E−10 20 −7.69343  1.34716E−04 −1.11390E−06 −4.77502E−08   7.36021E−10 24 −0.15276  7.48987E−05   5.45133E−06 −2.92926E−07   5.07897E−09

[0147] TABLE 43 variable distance: f d1 d2 d3 d4 d5 Wide 7.406 1.00011.590 6.594 3.589 2.113 Mean 15.940 6.514 6.075 2.908 6.538 2.662 Tele34.806 11.610 1.000 1.000 9.555 1.710

[0148] TABLE 44 parameter values of the conditional formula: Σd/(ft −fw) 2.025 f12t/f1 −1.447 (d3w − d3t)/(d1t − d1w) 0.527 Σd/(Z × y′) 2.540−f2/fw 1.082

[0149] The construction of the zoom lens of Example 11 is illustrated inFIG. 13, and the aberration curves are illustrated in FIG. 24.

[0150] Further, it is needless to say that in the zoom lenses of Example1 through Example 11, all of the non-spherical surfaces can be glassnon-spherical surfaces or hybrid non-spherical surfaces.

[0151] Example 3 illustrates an exemplary zoom lens in which thediameter of the aperture diaphragm at the long focal length end is madelarger than a diameter of an aperture diaphragm at the short focallength end and the F number at the long focal length end is made small.

[0152] Every zoom lenses of Example 1 through Example 11 have arelatively wide field angle with a half field angle equal to orexceeding 30° at the short focal length end despite that the number oflenses constituting each zoom lens is relatively small, i.e., 12, andthe size of each zoom lens is extremely small, and are satisfactory inperformance through the entire range of zooming despite that the zoomingratio is relatively high, i.e., about 4.5 times or more.

[0153]FIG. 25 illustrates a concept of a digital camera according to anembodiment of the present invention, using a zoom lens of the presentinvention. A photographing device 1 includes a photographing zoomoptical system 2 photographing an object, and a photographing element 3,such as a CCD, a CMOS sensor, etc., photo-electrically converting animage of the object imaged by the photographing zoom optical system 2. Afinder optical system 15 for observing a photographing range may beprovided. Further, a display device 12 for displaying a photographingrange, e.g. a liquid crystal display (LCD) device, may be provided.

[0154]FIG. 26 illustrates an exemplary control system of thephotographing device 1. The photographing zoom optical system 2 includesa photographing zoom lens 21 according to any of Example 1 throughExample 11, and a mechanical device 22. The mechanical device 22includes for example an auto-focusing mechanism, a mechanical shuttermechanism, and a zooming mechanism for changing distances between lensgroups of the zoom lens 21.

[0155] An image of an object is imaged by the photographing zoom opticalsystem 2 on the CCD 3 as the photographing element, and isphoto-electrically converted, after color separation by a filter (notshown) arranged on the CCD 3, into analogue image signals of red, greenand blue. The analogue signals outputted from the CCD 3 are processed ata signal processing part 4. For example, noise of the image signals isreduced by a correlation double sampling (CDS) circuit (not shown), andthe level of the image signals is adjusted by an automatic gain control(AGC) circuit (not shown).

[0156] The image signals are then converted to digital image data of anoptimal sampling frequency at an A/D converter 5.

[0157] The image data is then processed at a digital signal processingpart 6. For example, white balancing adjustment for adjusting gains ofred and green and separation of the image data into color differencedata and brightness data are performed.

[0158] The image data is then temporarily stored in an image memory 7.

[0159] A controller 8 includes a CPU, a ROM, a RAM, etc., and the CPUperforms controlling of the whole system according to a program storedin the ROM using the RAM as a working area. For example, a motor driver9 drives the mechanical device 22 of the photographing zoom opticalsystem 2 according to a control signal from the controller 8. A timingcontrol circuit 10 performs control of timings of generation of a drivecontrol signal for the CCD 3, signal processing at the signal processingpart 4, and A/D conversion at the A/D converter 5.

[0160] The digital camera in this example includes a data recording part11 for recording a photographed image in a recording medium, such as aflash memory card, etc. The digital camera further includes the displaydevice 12 for displaying a photographing range, e.g. a liquid crystaldisplay (LCD) device, as described earlier.

[0161] Further, the digital camera may include a strobe device 13 forphotographing a dark object. When an object is dark, by illuminating theobject by the strobe device 13, photographing of the dark object isenabled.

[0162]FIG. 26 further illustrates a concept of a portable informationterminal apparatus according to an embodiment of the present invention.As illustrated in figure, the portable information terminal apparatusincludes the above-described digital camera apparatus of the presentinvention and a communication I/F 14 for transmitting data recorded bythe digital camera to a personal computer 20, for example, viacommunication. Thus, by incorporating a communication function into adigital camera of the present invention, a compact, light, inexpensive,and energy saving information terminal apparatus is realized.

[0163]FIG. 27 illustrates a major part of a single lens reflex typedigital camera according to an embodiment of the present invention. Thephotographing zoom optical system 2 includes any of the zoom lenses ofExample 1 through Example 11, and the CCD 3 is arranged via a focalplane type shutter (not shown) in a predetermined position at a rearside of the optical system 2.

[0164] A mirror 16 is arranged between the shutter and the photographingzoom optical system 2. The mirror 16 is normally supported at the angleof 45° relative to an optical axis of the optical system 2 so that alight flux passing the photographing zoom optical system 2 is reflectedby a reflecting surface of the mirror 16 upward to serve as an observinglight flux. When photographing, the mirror 16 is moved upward to theposition illustrated by a dotted line 16 a, and thereby a light fluxpassing the photographing zoom optical system 2 advances straight toserve as a photographing light flux imaging an image of a photographedobject on the CCD 3.

[0165] A focal point plate 17 is arranged above the mirror 16 and anincident surface of a pentagonal prism 18 is arranged above the focalpoint plate 17. An eyepiece lens 19 is arranged at the rear of anemerging surface of the pentagonal prism 18, so that an erect image ofan object having no parallax can be observed through the eyepiece lens19.

[0166] A part of the mirror 16 can be a half mirror surface forseparating a distance measuring light flux, and a known auto-focusingoptical system may be provided at the rear of the mirror 16. Further, byarranging a silver film instead of the CCD 3, a single lens reflexcamera using a silver film can be realized.

[0167] Numerous additional modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that within the scope of the appended claims, thepresent invention may be practiced otherwise than as specificallydescribed herein.

[0168] The present application claims priority and contains subjectmatter related to Japanese Patent Applications NO. 2001-333060 and No.2002-188076 filed in the Japanese Patent Office on Oct. 30, 2001 andJun. 27, 2002, respectively, and the entire contents of which are herebyincorporated by reference.

What is clamed is:
 1. A zoom lens, comprising: a first lens group havinga positive refracting power; a second lens group having a negativerefracting power; a third lens group having a positive refracting power;a fourth lens group having a positive refracting power; and a fifth lensgroup having a positive refracting power, wherein the first lens group,the second group lens, the third lens group, the fourth lens group, andthe fifth lens group are arranged in succession, wherein the zoom lensis configured such that when zooming from a short focal length endtoward a long focal length end, the second lens group lens moves towardthe third lens group and the fourth lens group moves toward a side ofthe third lens group, and wherein when a distance from a first lenssurface of the zoom lens to the imaging plane of the zoom lens at thelong focal length end is Σd, a synthesized focal length of the firstlens group through the fifth lens group is fw, and a synthesized focallength of the first lens group through the fifth lens group is ft, afollowing conditional formula is satisfied: 1.45<Σd/(ft−fw)<2.2.
 2. Thezoom lens according to claim 1, wherein the first lens group is mountedat a fixed position.
 3. The zoom lens according to claim 1, wherein thethird lens group is mounted at a fixed position and includes an aperturediaphragm arranged at an outermost position at a side of the second lensgroup.
 4. The zoom lens according to claim 1, wherein focusing of thezoom lens is achieved by movement of the fifth lens group.
 5. The zoomlens according to claim 1, wherein when a synthesized focal length ofthe first lens group is f1 and a synthesized focal length of the firstlens group and the second lens group at the long focal length end isf12t, a following conditional formula is satisfied: −1.8<f12t/f1<−1.1.6. The zoom lens according to claim 1, wherein when a distance betweenthe first lens group and the second lens group at the short focal lengthend is d1w, a distance between the first lens group and the second lensgroup at the long focal length end is d1t, a distance between the thirdlens group and the fourth lens group at the short focal length end isd3w, and a distance between the third lens group and the fourth lensgroup at the long focal length end is d3t, a following conditionalformula is satisfied: 0.3<(d3w−d3t)/(d1t−d1w)<0.8.
 7. The zoom lensaccording to claim 1, wherein each of the first lens group and thesecond lens group includes three pieces of lens, the fourth lens groupincludes four pieces of lens, and the fifth lens group includes onepiece of lens, and wherein each of the second lens group through thefifth lens group includes one or more non-spherical surfaces.
 8. Thezoom lens according to claim 1, wherein a diameter of an aperturediaphragm at the long focal length end is greater than a diameter of anaperture diaphragm at the short focal length end.
 9. The zoom lensaccording to claim 1, wherein the zooms lens is configured to serve as aphotographing zoom lens with the first lens group arranged at a side ofan object.
 10. A zoom lens comprising: a first lens group having apositive refracting power; a second lens group having a negativerefracting power; a third lens group having a positive refracting power;a fourth lens group having a positive refracting power; and a fifth lensgroup having a positive refracting power, wherein the first lens group,the second group lens, the third lens group, the fourth lens group, andthe fifth lens group are arranged in succession, wherein the zoom lensis configured such that when zooming from a short focal length endtoward a long focal length end, at least a distance between the firstlens group and the second lens group increases, and a distance betweenthe second lens group and the third lens group and a distance betweenthe third lens group and the fourth lens group decrease, and whereinwhen a distance from a first lens surface of the zoom lens to an imagingplane of the zoom lens at the long focal length end is Σd, an imageheight is y′, and a zooming ratio is Z, a following conditional formulais satisfied: Σd/(Z×y′)<3.5.
 11. The zoom lens according to claim 10,wherein the first lens group is mounted at a fixed position.
 12. Thezoom lens according to claim 10, wherein the third lens group is mountedat a fixed position and includes an aperture diaphragm arranged at anoutermost position at a side of the second lens group.
 13. The zoom lensaccording to claim 10, wherein when a focal length of the second lensgroup is f2, a synthesized focal length of the first lens group throughthe fifth lens group at the short focal length end is fw, a followingconditional formula is satisfied: 0.68<−f2/fw<2.0.
 14. The zoom lensaccording to claim 10, wherein focusing of the zoom lens is achieved bymovement of the fifth lens group.
 15. The zoom lens according to claim10, wherein each of the first lens group and the second lens groupincludes three pieces of lens, the fourth lens group includes three orfour pieces of lens, and the fifth lens group includes one piece oflens.
 16. The zoom lens according to claim 15, wherein each of the firstlens group through the third lens group includes one or morenon-spherical surfaces.
 17. The zoom lens according to claim 15, whereinthe first lens group includes a negative lens and a first positive lensthat are joined, and a second positive lens.
 18. The zoom lens accordingto claim 15, wherein the second lens group includes a first negativelens, and a second negative lens and a positive lens that are joined.19. The zoom lens according to claim 10, wherein a diameter of anaperture diaphragm at the long focal length end is greater than adiameter of an aperture diaphragm at the short focal length end.
 20. Thezoom lens according to claim 10, wherein the zooms lens is configured toserve as a photographing zoom lens with the first lens group arranged ata side of an object.
 21. A camera apparatus comprising: a photographingzoom optical system imaging an image of an object; and a light receivingelement receiving a light of the image of the object imaged by thephotographing zoom optical system, wherein the photographing zoomoptical system includes a zoom lens having a first lens group having apositive refracting power, a second lens group having a negativerefracting power, a third lens group having a positive refracting power,a fourth lens group having a positive refracting power, and a fifth lensgroup having a positive refracting power, wherein the first lens group,the second group lens, the third lens group, the fourth lens group, andthe fifth lens group are arranged in succession, wherein the zooms lensis configured to serve as a photographing zoom lens with the first lensgroup arranged at a side of the object, and wherein the zoom lens isconfigured such that when zooming from a short focal length end toward along focal length end, the second lens group lens moves toward the thirdlens group and the fourth lens group moves toward a side of the thirdlens group, and when a distance from a first lens surface of the zoomlens to the imaging plane of the zoom lens at the long focal length endis Σd, a synthesized focal length of the first lens group through thefifth lens group is fw, and a synthesized focal length of the first lensgroup through the fifth lens group is ft, a following conditionalformula is satisfied: 1.45<Σd/(ft−fw)<2.2.
 22. The camera apparatusaccording to claim 21, wherein the zoom lens is configured such that thefirst lens group is mounted at a fixed position.
 23. The cameraapparatus according to claim 21, wherein the zoom lens is configuredsuch that the third lens group of the zoom lens is mounted at a fixedposition and includes an aperture diaphragm arranged at an outermostposition at a side of the second lens group.
 24. The camera apparatusaccording to claim 21, wherein the zoom lens is configured such thatfocusing of the zoom lens is achieved by movement of the fifth lensgroup.
 25. The camera apparatus according to claim 21, wherein the zoomlens is configured such that when a synthesized focal length of thefirst lens group is f1 and a synthesized focal length of the first lensgroup and the second lens group at the long focal length end is f12t, afollowing conditional formula is satisfied: −1.8<f12t/f1<−1.1.
 26. Thecamera apparatus according to claim 21, wherein the zoom lens isconfigured such that when a distance between the first lens group andthe second lens group at the short focal length end is d1w, a distancebetween the first lens group and the second lens group at the long focallength end is d1t, a distance between the third lens group and thefourth lens group at the short focal length end is d3w, and a distancebetween the third lens group and the fourth lens group at the long focallength end is d3t, a following conditional formula is satisfied:0.3<(d3w−d3t)/(d1t−d1w)<0.8.
 27. The camera apparatus according to claim21, wherein the zoom lens is configured such that each of the first lensgroup and the second lens group includes three pieces of lens, thefourth lens group includes four pieces of lens, the fifth lens groupincludes one piece of lens, and each of the second lens group throughthe fifth lens group includes one or more non-spherical surfaces. 28.The camera apparatus according to claim 21, wherein the zoom lens isconfigured such that a diameter of an aperture diaphragm at the longfocal length end is greater than a diameter of an aperture diaphragm atthe short focal length end.
 29. The camera apparatus according to claim21, further comprising: a device configured to convert the light of theimage of the object received by the light receiving element into digitalinformation.
 30. The camera apparatus according to claim 21, wherein thelight receiving element has a number of picture elements equal to orgreater than 3 millions.
 31. A camera apparatus comprising: aphotographing zoom optical system imaging an image of an object; and alight receiving element receiving a light of the image of the objectimaged by the photographing zoom optical system, wherein thephotographing zoom optical system includes a zoom lens having a firstlens group having a positive refracting power; a second lens grouphaving a negative refracting power; a third lens group having a positiverefracting power; a fourth lens group having a positive refractingpower; and a fifth lens group having a positive refracting power,wherein the first lens group, the second group lens, the third lensgroup, the fourth lens group, and the fifth lens group are arranged insuccession, wherein the zooms lens is configured to serve as aphotographing zoom lens with the first lens group arranged at a side ofthe object, and wherein the zoom lens is configured such that whenzooming from a short focal length end toward a long focal length end, atleast a distance between the first lens group and the second lens groupincreases, and a distance between the second lens group and the thirdlens group and a distance between the third lens group and the fourthlens group decrease, and when a distance from a first lens surface ofthe zoom lens to an imaging plane of the zoom lens at the long focallength end is Σd, an image height is y′, and a zooming ratio is Z, afollowing conditional formula is satisfied: Σd/(Z×y′)<3.5.
 32. Thecamera apparatus according to claim 31, wherein the zoom lens isconfigured such that the first lens group is mounted at a fixedposition.
 33. The camera apparatus according to claim 31, wherein thezoom lens is configured such that the third lens group is mounted at afixed position and includes an aperture diaphragm arranged at anoutermost position at a side of the second lens group.
 34. The cameraapparatus according to claim 31, wherein the zoom lens is configuredsuch that when a focal length of the second lens group is f2 and asynthesized focal length of the first lens group through the fifth lensgroup at the short focal length end is fw, a following conditionalformula is satisfied: 0.68<−f2/fw<2.0.
 35. The camera apparatusaccording to claim 31, wherein the zoom lens is configured such thatfocusing of the zoom lens is achieved by movement of the fifth lensgroup.
 36. The camera apparatus according to claim 31, wherein the zoomlens is configured such that each of the first lens group and the secondlens group includes three pieces of lens, the fourth lens group includesthree or four pieces of lens, and the fifth lens group includes onepiece of lens.
 37. The camera apparatus according to claim 36, whereinthe zoom lens is configured such that each of the first lens groupthrough the third lens group includes one or more non-sphericalsurfaces.
 38. The camera apparatus according to claim 36, wherein thezoom lens is configured such that the first lens group includes anegative lens and a first positive lens that are joined, and a secondpositive lens.
 39. The camera apparatus according to claim 36, whereinthe zoom lens is configured such that the second lens group includes afirst negative lens, and a second negative lens and a positive lens thatare joined.
 40. The camera apparatus according to claim 31, wherein thezoom lens is configured such that a diameter of an aperture diaphragm atthe long focal length end is greater than a diameter of an aperturediaphragm at the short focal length end.
 41. The camera apparatusaccording to claim 31, further comprising: a device configured toconvert the light of the image of the object received by the lightreceiving element into digital information.
 42. The camera apparatusaccording to claim 31, wherein the light receiving element has a numberof picture elements equal to or greater than 3 millions.
 43. A portableinformation terminal apparatus comprising: a camera apparatus configuredto photograph an image of an object; and a communication interfaceconfigured to transmit via communication information of the image of theobject photographed by the camera apparatus, wherein the cameraapparatus includes a photographing zoom optical system imaging the imageof the object, and a light receiving element receiving a light of theimage of the object imaged by the photographing zoom optical system,wherein the photographing zoom optical system includes a zoom lenshaving a first lens group having a positive refracting power; a secondlens group having a negative refracting power; a third lens group havinga positive refracting power; a fourth lens group having a positiverefracting power; and a fifth lens group having a positive refractingpower, wherein the first lens group, the second group lens, the thirdlens group, the fourth lens group, and the fifth lens group are arrangedin succession, wherein the zooms lens is configured to serve as aphotographing zoom lens with the first lens group arranged at a side ofthe object, and wherein the zoom lens is configured such that whenzooming from a short focal length end toward a long focal length end,the second lens group lens moves toward the third lens group and thefourth lens group moves toward a side of the third lens group, andwherein when a distance from a first lens surface of the zoom lens tothe imaging plane of the zoom lens at the long focal length end is Σd, asynthesized focal length of the first lens group through the fifth lensgroup is fw, and a synthesized focal length of the first lens groupthrough the fifth lens group is ft, a following conditional formula issatisfied: 1.45<Σd/(ft−fw)<2.2.
 44. The portable information terminalapparatus according to claim 43, wherein the zoom lens is configuredsuch that the first lens group is mounted at a fixed position.
 45. Theportable information terminal apparatus according to claim 43, whereinthe zoom lens is configured such that the third lens group of the zoomlens is mounted at a fixed position and includes an aperture diaphragmarranged at an outermost position at a side of the second lens group.46. The portable information terminal apparatus according to claim 43,wherein the zoom lens is configured such that focusing of the zoom lensis achieved by movement of the fifth lens group.
 47. The portableinformation terminal apparatus according to claim 43, wherein the zoomlens is configured such that when a synthesized focal length of thefirst lens group is f1 and a synthesized focal length of the first lensgroup and the second lens group at the long focal length end is f12t, afollowing conditional formula is satisfied: −1.8<f12t/f1<−1.1.
 48. Theportable information terminal apparatus according to claim 43, whereinthe zoom lens is configured such that when a distance between the firstlens group and the second lens group at the short focal length end isd1w, a distance between the first lens group and the second lens groupat the long focal length end is d1t, a distance between the third lensgroup and the fourth lens group at the short focal length end is d3w,and a distance between the third lens group and the fourth lens group atthe long focal length end is d3t, a following conditional formula issatisfied: 0.3<(d3w−d3t)/(d1t−d1w)<0.8.
 49. The portable informationterminal apparatus according to claim 43, wherein the zoom lens isconfigured such that each of the first lens group and the second lensgroup includes three pieces of lens, the fourth lens group includes fourpieces of lens, the fifth lens group includes one piece of lens, andeach of the second lens group through the fifth lens group includes oneor more non-spherical surfaces.
 50. The portable information terminalapparatus according to claim 43, wherein the zoom lens is configuredsuch that a diameter of an aperture diaphragm at the long focal lengthend is greater than a diameter of an aperture diaphragm at the shortfocal length end.
 51. The portable information terminal apparatusaccording to claim 43, further comprising: a device configured toconvert the light of the image of the object received by the lightreceiving element into digital information.
 52. The portable informationterminal apparatus according to claim 43, wherein the light receivingelement has a number of picture elements equal to or greater than 3millions.
 53. A portable information terminal apparatus comprising: acamera apparatus configured to photograph an image of an object; and acommunication interface configured to transmit via communicationinformation of the image of the object photographed by the cameraapparatus, wherein the camera apparatus includes a photographing zoomoptical system imaging the image of the object, and a light receivingelement receiving a light of the image of the object imaged by thephotographing zoom optical system, wherein the photographing zoomoptical system includes a zoom lens having a first lens group having apositive refracting power; a second lens group having a negativerefracting power; a third lens group having a positive refracting power;a fourth lens group having a positive refracting power; and a fifth lensgroup having a positive refracting power, wherein the first lens group,the second group lens, the third lens group, the fourth lens group, andthe fifth lens group are arranged in succession, wherein the zooms lensis configured to serve as a photographing zoom lens with the first lensgroup arranged at a side of the object, and wherein the zoom lens isconfigured such that when zooming from a short focal length end toward along focal length end, at least a distance between the first lens groupand the second lens group increases, and a distance between the secondlens group and the third lens group and a distance between the thirdlens group and the fourth lens group decrease, and when a distance froma first lens surface of the zoom lens to an imaging plane of the zoomlens at the long focal length end is Σd, an image height is y′, and azooming ratio is Z, a following conditional formula is satisfied:Σd/(Z×y′)<3.5.
 54. The portable information terminal apparatus accordingto claim 53, wherein the zoom lens is configured such that the firstlens group is mounted at a fixed position.
 55. The portable informationterminal apparatus according to claim 53, wherein the zoom lens isconfigured such that the third lens group is mounted at a fixed positionand includes an aperture diaphragm arranged at a most outside positionat a side of the second lens group.
 56. The portable informationterminal apparatus according to claim 53, wherein the zoom lens isconfigured such that when a focal length of the second lens group is f2and a synthesized focal length of the first lens group through the fifthlens group at the short focal length end is fw, a following conditionalformula is satisfied: 0.68<−f2/fw<2.0.
 57. The portable informationterminal apparatus according to claim 53, wherein the zoom lens isconfigured such that focusing of the zoom lens is achieved by movementof the fifth lens group.
 58. The portable information terminal apparatusaccording to claim 53, wherein the zoom lens is configured such thateach of the first lens group and the second lens group includes threepieces of lens, the fourth lens group includes three or four pieces oflens, and the fifth lens group includes one piece of lens.
 59. Theportable information terminal apparatus according to claim 58, whereinthe zoom lens is configured such that each of the first lens groupthrough the third lens group includes one or more non-sphericalsurfaces.
 60. The portable information terminal apparatus according toclaim 58, wherein the zoom lens is configured such that the first lensgroup includes a negative lens and a first positive lens that arejoined, and a second positive lens.
 61. The portable informationterminal apparatus according to claim 58, wherein the zoom lens isconfigured such that the second lens group includes a first negativelens, and a second negative lens and a positive lens that are joined.62. The portable information terminal apparatus according to claim 53,wherein the zoom lens is configured such that a diameter of an aperturediaphragm at the long focal length end is greater than a diameter of anaperture diaphragm at the short focal length end.
 63. The portableinformation terminal apparatus according to claim 53, furthercomprising: a device configured to convert the light of the image of theobject received by the light receiving element into digital information.64. The portable information terminal apparatus according to claim 53,wherein the light receiving element has a number of picture elementsequal to or greater than 3 millions.
 65. A portable information terminalapparatus comprising: means for photographing an image of an object; andmeans for transmitting via communication information of the image of theobject photographed by the photographing means, wherein thephotographing means includes a photographing zoom optical system imagingthe image of the object, and a light receiving element receiving a lightof the image of the object imaged by the photographing zoom opticalsystem, wherein the photographing zoom optical system includes a zoomlens having a first lens group having a positive refracting power; asecond lens group having a negative refracting power; a third lens grouphaving a positive refracting power; a fourth lens group having apositive refracting power; and a fifth lens group having a positiverefracting power, wherein the first lens group, the second group lens,the third lens group, the fourth lens group, and the fifth lens groupare arranged in succession, wherein the zooms lens is configured toserve as a photographing zoom lens with the first lens group arranged ata side of the object, and wherein the zoom lens is configured such thatwhen zooming from a short focal length end toward a long focal lengthend, the second lens group lens moves toward the third lens group andthe fourth lens group moves toward a side of the third lens group, andwherein when a distance from a first lens surface of the zoom lens tothe imaging plane of the zoom lens at the long focal length end is Σd, asynthesized focal length of the first lens group through the fifth lensgroup is fw, and a synthesized focal length of the first lens groupthrough the fifth lens group is ft, a following conditional formula issatisfied: 1.45<Σd/(ft−fw)<2.2.